// https://csrc.nist.gov/csrc/media/publications/fips/197/final/documents/fips-197.pdf
// https://csrc.nist.gov/csrc/media/projects/cryptographic-standards-and-guidelines/documents/aes-development/rijndael-ammended.pdf#page=19
// https://link.springer.com/content/pdf/10.1007/3-540-36400-5_13.pdf
// http://asmaes.sourceforge.net/rijndael/rijndaelImplementation.pdf
// https://www.movable-type.co.uk/scripts/aes.html
import { BlockCiper, BlockCiperOperation } from "./block_ciper_operator.ts";
import type { BlockCiperConfig } from "./common.ts";
import type { AESBase } from "./aes_base.ts";

// deno-fmt-ignore
const SBOX: number[] = [
  0x63,
  0x7c,
  0x77,
  0x7b,
  0xf2,
  0x6b,
  0x6f,
  0xc5,
  0x30,
  0x01,
  0x67,
  0x2b,
  0xfe,
  0xd7,
  0xab,
  0x76,
  0xca,
  0x82,
  0xc9,
  0x7d,
  0xfa,
  0x59,
  0x47,
  0xf0,
  0xad,
  0xd4,
  0xa2,
  0xaf,
  0x9c,
  0xa4,
  0x72,
  0xc0,
  0xb7,
  0xfd,
  0x93,
  0x26,
  0x36,
  0x3f,
  0xf7,
  0xcc,
  0x34,
  0xa5,
  0xe5,
  0xf1,
  0x71,
  0xd8,
  0x31,
  0x15,
  0x04,
  0xc7,
  0x23,
  0xc3,
  0x18,
  0x96,
  0x05,
  0x9a,
  0x07,
  0x12,
  0x80,
  0xe2,
  0xeb,
  0x27,
  0xb2,
  0x75,
  0x09,
  0x83,
  0x2c,
  0x1a,
  0x1b,
  0x6e,
  0x5a,
  0xa0,
  0x52,
  0x3b,
  0xd6,
  0xb3,
  0x29,
  0xe3,
  0x2f,
  0x84,
  0x53,
  0xd1,
  0x00,
  0xed,
  0x20,
  0xfc,
  0xb1,
  0x5b,
  0x6a,
  0xcb,
  0xbe,
  0x39,
  0x4a,
  0x4c,
  0x58,
  0xcf,
  0xd0,
  0xef,
  0xaa,
  0xfb,
  0x43,
  0x4d,
  0x33,
  0x85,
  0x45,
  0xf9,
  0x02,
  0x7f,
  0x50,
  0x3c,
  0x9f,
  0xa8,
  0x51,
  0xa3,
  0x40,
  0x8f,
  0x92,
  0x9d,
  0x38,
  0xf5,
  0xbc,
  0xb6,
  0xda,
  0x21,
  0x10,
  0xff,
  0xf3,
  0xd2,
  0xcd,
  0x0c,
  0x13,
  0xec,
  0x5f,
  0x97,
  0x44,
  0x17,
  0xc4,
  0xa7,
  0x7e,
  0x3d,
  0x64,
  0x5d,
  0x19,
  0x73,
  0x60,
  0x81,
  0x4f,
  0xdc,
  0x22,
  0x2a,
  0x90,
  0x88,
  0x46,
  0xee,
  0xb8,
  0x14,
  0xde,
  0x5e,
  0x0b,
  0xdb,
  0xe0,
  0x32,
  0x3a,
  0x0a,
  0x49,
  0x06,
  0x24,
  0x5c,
  0xc2,
  0xd3,
  0xac,
  0x62,
  0x91,
  0x95,
  0xe4,
  0x79,
  0xe7,
  0xc8,
  0x37,
  0x6d,
  0x8d,
  0xd5,
  0x4e,
  0xa9,
  0x6c,
  0x56,
  0xf4,
  0xea,
  0x65,
  0x7a,
  0xae,
  0x08,
  0xba,
  0x78,
  0x25,
  0x2e,
  0x1c,
  0xa6,
  0xb4,
  0xc6,
  0xe8,
  0xdd,
  0x74,
  0x1f,
  0x4b,
  0xbd,
  0x8b,
  0x8a,
  0x70,
  0x3e,
  0xb5,
  0x66,
  0x48,
  0x03,
  0xf6,
  0x0e,
  0x61,
  0x35,
  0x57,
  0xb9,
  0x86,
  0xc1,
  0x1d,
  0x9e,
  0xe1,
  0xf8,
  0x98,
  0x11,
  0x69,
  0xd9,
  0x8e,
  0x94,
  0x9b,
  0x1e,
  0x87,
  0xe9,
  0xce,
  0x55,
  0x28,
  0xdf,
  0x8c,
  0xa1,
  0x89,
  0x0d,
  0xbf,
  0xe6,
  0x42,
  0x68,
  0x41,
  0x99,
  0x2d,
  0x0f,
  0xb0,
  0x54,
  0xbb,
  0x16,
];

// deno-fmt-ignore
const INV_SBOX: number[] = [
  0x52,
  0x09,
  0x6a,
  0xd5,
  0x30,
  0x36,
  0xa5,
  0x38,
  0xbf,
  0x40,
  0xa3,
  0x9e,
  0x81,
  0xf3,
  0xd7,
  0xfb,
  0x7c,
  0xe3,
  0x39,
  0x82,
  0x9b,
  0x2f,
  0xff,
  0x87,
  0x34,
  0x8e,
  0x43,
  0x44,
  0xc4,
  0xde,
  0xe9,
  0xcb,
  0x54,
  0x7b,
  0x94,
  0x32,
  0xa6,
  0xc2,
  0x23,
  0x3d,
  0xee,
  0x4c,
  0x95,
  0x0b,
  0x42,
  0xfa,
  0xc3,
  0x4e,
  0x08,
  0x2e,
  0xa1,
  0x66,
  0x28,
  0xd9,
  0x24,
  0xb2,
  0x76,
  0x5b,
  0xa2,
  0x49,
  0x6d,
  0x8b,
  0xd1,
  0x25,
  0x72,
  0xf8,
  0xf6,
  0x64,
  0x86,
  0x68,
  0x98,
  0x16,
  0xd4,
  0xa4,
  0x5c,
  0xcc,
  0x5d,
  0x65,
  0xb6,
  0x92,
  0x6c,
  0x70,
  0x48,
  0x50,
  0xfd,
  0xed,
  0xb9,
  0xda,
  0x5e,
  0x15,
  0x46,
  0x57,
  0xa7,
  0x8d,
  0x9d,
  0x84,
  0x90,
  0xd8,
  0xab,
  0x00,
  0x8c,
  0xbc,
  0xd3,
  0x0a,
  0xf7,
  0xe4,
  0x58,
  0x05,
  0xb8,
  0xb3,
  0x45,
  0x06,
  0xd0,
  0x2c,
  0x1e,
  0x8f,
  0xca,
  0x3f,
  0x0f,
  0x02,
  0xc1,
  0xaf,
  0xbd,
  0x03,
  0x01,
  0x13,
  0x8a,
  0x6b,
  0x3a,
  0x91,
  0x11,
  0x41,
  0x4f,
  0x67,
  0xdc,
  0xea,
  0x97,
  0xf2,
  0xcf,
  0xce,
  0xf0,
  0xb4,
  0xe6,
  0x73,
  0x96,
  0xac,
  0x74,
  0x22,
  0xe7,
  0xad,
  0x35,
  0x85,
  0xe2,
  0xf9,
  0x37,
  0xe8,
  0x1c,
  0x75,
  0xdf,
  0x6e,
  0x47,
  0xf1,
  0x1a,
  0x71,
  0x1d,
  0x29,
  0xc5,
  0x89,
  0x6f,
  0xb7,
  0x62,
  0x0e,
  0xaa,
  0x18,
  0xbe,
  0x1b,
  0xfc,
  0x56,
  0x3e,
  0x4b,
  0xc6,
  0xd2,
  0x79,
  0x20,
  0x9a,
  0xdb,
  0xc0,
  0xfe,
  0x78,
  0xcd,
  0x5a,
  0xf4,
  0x1f,
  0xdd,
  0xa8,
  0x33,
  0x88,
  0x07,
  0xc7,
  0x31,
  0xb1,
  0x12,
  0x10,
  0x59,
  0x27,
  0x80,
  0xec,
  0x5f,
  0x60,
  0x51,
  0x7f,
  0xa9,
  0x19,
  0xb5,
  0x4a,
  0x0d,
  0x2d,
  0xe5,
  0x7a,
  0x9f,
  0x93,
  0xc9,
  0x9c,
  0xef,
  0xa0,
  0xe0,
  0x3b,
  0x4d,
  0xae,
  0x2a,
  0xf5,
  0xb0,
  0xc8,
  0xeb,
  0xbb,
  0x3c,
  0x83,
  0x53,
  0x99,
  0x61,
  0x17,
  0x2b,
  0x04,
  0x7e,
  0xba,
  0x77,
  0xd6,
  0x26,
  0xe1,
  0x69,
  0x14,
  0x63,
  0x55,
  0x21,
  0x0c,
  0x7d,
];

const RCON = [0x00, 0x01, 0x02, 0x04, 0x08, 0x10, 0x20, 0x40, 0x80, 0x1b, 0x36];

function xtime(n: number, x: number): number {
  if (x === 1) return n;

  let output = 0;
  let multiply = n;

  while (x > 0) {
    if (x & 0x01) output ^= multiply;
    multiply = multiply & 0x80 ? (multiply << 1) ^ 0x011b : multiply << 1;
    x = x >> 1;
  }

  return output & 0xff;
}

function rotWord(keySchedule: Uint8Array, column: number) {
  const offset = column * 4;
  const tmp = keySchedule[offset];
  keySchedule[offset] = keySchedule[offset + 1];
  keySchedule[offset + 1] = keySchedule[offset + 2];
  keySchedule[offset + 2] = keySchedule[offset + 3];
  keySchedule[offset + 3] = tmp;
}

function subWord(keySchedule: Uint8Array, column: number) {
  const offset = column * 4;
  for (let i = 0; i < 4; i++) {
    keySchedule[offset + i] = SBOX[keySchedule[offset + i]];
  }
}

function keyExpansion(key: Uint8Array) {
  const Nb = 4;
  const Nk = key.length / 4;
  const Nr = Nk + 6;

  const keySchedule = new Uint8Array(16 * (Nr + 1));
  keySchedule.set(key, 0);

  for (let i = Nk; i < Nb * (Nr + 1); i++) {
    const prevOffset = (i - Nk) * 4;
    const offset = i * 4;

    keySchedule[offset] = keySchedule[offset - 4];
    keySchedule[offset + 1] = keySchedule[offset - 3];
    keySchedule[offset + 2] = keySchedule[offset - 2];
    keySchedule[offset + 3] = keySchedule[offset - 1];

    if (i % Nk === 0) {
      rotWord(keySchedule, i);
      subWord(keySchedule, i);
      keySchedule[offset] ^= RCON[i / Nk];
    } else if (Nk > 6 && i % Nk === 4) {
      subWord(keySchedule, i);
    }

    keySchedule[offset] ^= keySchedule[prevOffset];
    keySchedule[offset + 1] ^= keySchedule[prevOffset + 1];
    keySchedule[offset + 2] ^= keySchedule[prevOffset + 2];
    keySchedule[offset + 3] ^= keySchedule[prevOffset + 3];
  }

  return keySchedule;
}

class AESBlockCiper implements BlockCiper {
  protected keySchedule: Uint8Array;

  constructor(key: Uint8Array) {
    this.keySchedule = keyExpansion(key);
  }

  subBytes(block: Uint8Array) {
    for (let i = 0; i < block.length; i++) {
      block[i] = SBOX[block[i]];
    }
  }

  inverseSubBytes(block: Uint8Array) {
    for (let i = 0; i < block.length; i++) {
      block[i] = INV_SBOX[block[i]];
    }
  }

  shiftRow(block: Uint8Array) {
    let t = block[1];
    block[1] = block[5];
    block[5] = block[9];
    block[9] = block[13];
    block[13] = t;

    t = block[10];
    block[10] = block[2];
    block[2] = t;
    t = block[14];
    block[14] = block[6];
    block[6] = t;

    t = block[15];
    block[15] = block[11];
    block[11] = block[7];
    block[7] = block[3];
    block[3] = t;
  }

  inverseShiftRow(block: Uint8Array) {
    let t = block[13];
    block[13] = block[9];
    block[9] = block[5];
    block[5] = block[1];
    block[1] = t;

    t = block[10];
    block[10] = block[2];
    block[2] = t;
    t = block[14];
    block[14] = block[6];
    block[6] = t;

    t = block[3];
    block[3] = block[7];
    block[7] = block[11];
    block[11] = block[15];
    block[15] = t;
  }

  protected addRoundKey(state: Uint8Array, round: number) {
    for (let i = 0; i < 16; i++) {
      state[i] ^= this.keySchedule[round * 16 + i];
    }
  }

  mixColumn(block: Uint8Array) {
    for (let i = 0; i < 4; i++) {
      const offset = i * 4;
      const a = [
        block[offset],
        block[offset + 1],
        block[offset + 2],
        block[offset + 3],
      ];

      block[offset] = xtime(a[0], 0x2) ^
        xtime(a[1], 0x3) ^
        xtime(a[2], 0x1) ^
        xtime(a[3], 0x1);
      block[offset + 1] = xtime(a[0], 0x1) ^
        xtime(a[1], 0x2) ^
        xtime(a[2], 0x3) ^
        xtime(a[3], 0x1);
      block[offset + 2] = xtime(a[0], 0x1) ^
        xtime(a[1], 0x1) ^
        xtime(a[2], 0x2) ^
        xtime(a[3], 0x3);
      block[offset + 3] = xtime(a[0], 0x3) ^
        xtime(a[1], 0x1) ^
        xtime(a[2], 0x1) ^
        xtime(a[3], 0x2);
    }
  }

  inverseMixColumn(block: Uint8Array) {
    for (let i = 0; i < 4; i++) {
      const offset = i * 4;
      const a = [
        block[offset],
        block[offset + 1],
        block[offset + 2],
        block[offset + 3],
      ];

      block[offset] = xtime(a[0], 0xe) ^
        xtime(a[1], 0xb) ^
        xtime(a[2], 0xd) ^
        xtime(a[3], 0x9);
      block[offset + 1] = xtime(a[0], 0x9) ^
        xtime(a[1], 0xe) ^
        xtime(a[2], 0xb) ^
        xtime(a[3], 0xd);
      block[offset + 2] = xtime(a[0], 0xd) ^
        xtime(a[1], 0x9) ^
        xtime(a[2], 0xe) ^
        xtime(a[3], 0xb);
      block[offset + 3] = xtime(a[0], 0xb) ^
        xtime(a[1], 0xd) ^
        xtime(a[2], 0x9) ^
        xtime(a[3], 0xe);
    }
  }

  encrypt(m: Uint8Array): Uint8Array {
    const nb = 4;
    const nr = this.keySchedule.length / 16 - 1;

    const state = new Uint8Array(m);
    this.addRoundKey(state, 0);

    for (let i = 1; i < nr; i++) {
      this.subBytes(state);
      this.shiftRow(state);
      this.mixColumn(state);
      this.addRoundKey(state, i);
    }

    this.subBytes(state);
    this.shiftRow(state);
    this.addRoundKey(state, nr);

    return state;
  }

  decrypt(m: Uint8Array): Uint8Array {
    const nb = 4;
    const nr = this.keySchedule.length / 16 - 1;

    const state = new Uint8Array(m);
    this.addRoundKey(state, nr);

    for (let i = nr - 1; i > 0; i--) {
      this.inverseShiftRow(state);
      this.inverseSubBytes(state);
      this.addRoundKey(state, i);
      this.inverseMixColumn(state);
    }

    this.inverseShiftRow(state);
    this.inverseSubBytes(state);
    this.addRoundKey(state, 0);

    return state;
  }
}

export class PureAES implements AESBase {
  protected ciper: AESBlockCiper;
  protected config?: BlockCiperConfig;

  constructor(key: Uint8Array, config?: BlockCiperConfig) {
    this.ciper = new AESBlockCiper(key);
    this.config = config;
  }

  async encrypt(m: Uint8Array): Promise<Uint8Array> {
    return BlockCiperOperation.encrypt(m, this.ciper, 16, this.config);
  }

  async decrypt(m: Uint8Array): Promise<Uint8Array> {
    return BlockCiperOperation.decrypt(m, this.ciper, 16, this.config);
  }
}
